Embryology

Question 1

What are the two steps in the heart reaching its final position?

Answer 1

1. Lateral folding

2. Cranio-caudal folding

Question 2

How many dilatations does the heart tube develop, and what do these structures turn into?

Answer 2

5 dilatations

Develop into the adult heart structures

Question 3

What two adult derivatives does the truncus arteriosus form?

Answer 3

Aorta and pulmonary trunk

Question 4

What two adult derivates does the bulbus cordis form?

Answer 4

1. Trabeculated part of right ventricle

2. Outflow part of both ventricles

Question 5

What adult derivative does the ventricle of the heart tube form?

Answer 5

Trabeculated part of left ventricle

Question 6

What adult derivative of the atrium of the heart tube is formed?

Answer 6

Trabeculated part of both atria

Question 7

What two adult derivatives of the sinus venosus of heart tube are formed?

Answer 7

1. Smooth part of right atrium

2. Coronary sinus

Question 8

What occurs on day 23?

Answer 8

The heart begins to loop and fold

Question 9

On day 23, when looping and folding - what happens to the atrium?

Answer 9

Dorsal and cranial

Question 10

On day 23, when looping and folding, what happens to the ventricle?

Answer 10

Displaced left

Question 11

On day 23 - when looping and folding, what happens to the bulbus cordis?

Answer 11

Inferiorly, ventrally to the right

Question 12

What are the 4 steps in atrial septation?

Answer 12

1. Septum primum
2. Ostium secundum
3. Septum secundum
4. Foramen Ovale

Question 13

Give the two steps in ventricular septation?

Answer 13

1. Muscular septum

2. Membranius septum

Question 14

Give two features of outflow tract septation

Answer 14

1. Spiral septum from the conotruncal ridges

2. Closely linked to formation of membranous part of ventricular septum

Question 15

What week does remodelling of atria occur?

Answer 15

Week 5

Question 16

What development involves 6 pairs, associated with the pharyngeal arches?

Answer 16

Development of the aortic arches

Question 17

What happens to pairs 1 & 2 in development of the aortic arches?

Answer 17

Mostly obliterated

Question 18

What happens to the 5th pair during development of the aortic arches?

Answer 18

Rudimentary or absent

Question 19

What two things does the 3rd pair become during development of the aortic arches?

Answer 19

1. Common carotid

2. First part of ICE

Question 20

What two things does the 4th pair become during development of the aortic arches?

Answer 20

1. Right subclavian

2. Part of aortic arch

Question 21

What two things does the 6th pair become, during the development of the aortic arches?

Answer 21

1. Sprout branches that form pulmonary aa

2. Ductus arteriosus on left

Question 22

What role do the vitelline veins have?

Answer 22

Drain yolk sac

Question 23

What role do the umbilical veins have?

Answer 23

Oxygenated blood from placenta

Question 24

What role do the cardinal veins have?

Answer 24

Gives systemic venous system

Question 25

What are 3 features of vitelline veins?

Answer 25

1. Portal venous system draining gut
2. Hepatic sinusoids and veins
3. Hepatic portion of IVC

Question 26

Give two features of umbilical veins?

Answer 26

1. Right degenerates

2. Left remains as definitive umbilical vein

Question 27

What do the systemic veins - anterior cardinal veins do?

Answer 27

Drain head and neck

Question 28

Name the two anterior cardinal veins?

Answer 28

1. Jugular system and left brachiocephalic vein

2. SVC

Question 29

Name the 4 posterior cardinal veins?

Answer 29

1. Azygos and hemiazygos systems (body wall)
2. Gonadal and renal veins
3. Iliac veins
4. IVC

Question 30

What do the posterior cardinal veins do?

Answer 30

Drain trunk

Question 31

Give two features of the primary heart field?

Answer 31

1. Visceral mesoderm

2. Cranial to the developing neural tube